Haiti cholera epidemic worse than expected

29th March 2011

The cholera epidemic crippling the country of Haiti will probably be far worse than governments predicted, according to a recent US study.

Researchers said that, rather than infecting 400,000, the disease could strike almost 800,000 people, and that governments around the world needed to combine their efforts to stem the progress of the epidemic.

Prior to the outbreak last year, Haiti had not had a cholera epidemic in 100 years.

The epidemic followed a devastating earthquake, which uprooted hundreds of thousands of people.

Researchers used a new type of mathematical model to predict the progress of the epidemic around the country.

The new model forecasts over 11,000 deaths by the end of November, if levels of treatment remain the same.

Study co-author Jason Andrews, a research fellow at the Harvard School of Public Health, said that the UN estimate was based on an erroneous assumption arrived at by guesswork.

He said that the UN had ignored the dynamics of cholera epidemics when making its prediction.

In the recent study, the researchers not only used well-established mathematical methods to forecast the impact of the disease and its progress, but also predicted the impact the disease would have on drinking water and on the distribution of vaccines and medicine.

Using the model, the authors predicted that governments could prevent 170,000 cases of cholera and 3,400 deaths by lending a hand to medical teams operating in Haiti.

The researchers calculated that vaccinating 10% of the population of Haiti would prevent 63,000 cases of the disease, amounting to about 900 deaths.

They found that treating about half of all cases based on severity would prevent a further 1,300 deaths.

Andrews said that fighting the cholera epidemic in Haiti would need serious investment from the international community, requiring two million doses of vaccine.

But Marcos Espinal, head of health surveillance, disease prevention and control at the Pan American Health Organisation (PAHO), defended the UN's forecast about the epidemic.

He said that the UN's projection had not yet been proven wrong.

But the recent study was not the first to highlight the potential inaccuracy of the UN's first cholera estimate.

A few weeks ago, another US team of researchers predicted that the cholera epidemic in Haiti would be bigger than expected.

Those researchers also said that the UN's estimates were crude, based on a single number and a single assumption about the spread of the disease.

Sanjay Basu, of the University of California in San Fransisco, said at the time that the epidemic would be larger than predicted in terms of sheer numbers, lasting far longer than governments had originally believed.